Chimeric genes and transgenic plants are used to study the regulation of genes involved in symbiotic plant-microbe interactions (nodulin genes).
Nodulin genes are plant genes specifically activated during the formation of nitrogen-fixing nodules on leguminous plants. These genes are interesting to study since they are not only induced in a specific developmental fashion by signals coming directly or indirectly from the rhizobial symbiont, but are also expressed in a tissue-specific manner. By examining the expression of chimeric nodulin-reporter genes in transgenic legume plants it has been shown that nodule specific expression is mediated by DNA sequences present in the 5 upstream region of several nodulin genes. Here we summarize the available data on these cis-acting elements and the trans-acting factors interacting with them. We also review experiments designed to identify rhizobial "signals" which may play a role in nodule specific gene expression.
de Bruijn
F J
FJ
Max-Plank-Institut für Züchtungsforschung, Köln, Federal Republic of Germany.
Szabados
L
L
Schell
J
J
D001483:Base Sequence; D004274:DNA, Recombinant; D005786:Gene Expression Regulation; D017343:Genes, Plant; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics* / Q000382:microbiology; D011401:Promoter Regions, Genetic; D012231:Rhizobium / Q000235:genetics / Q000502:physiology*; D013559:Symbiosis
D004274:DNA, Recombinant; D008565:Membrane Proteins; D010940:Plant Proteins; C045625:nodulin